Coating compositions and method for forming a self-healing corrosion preventative film

ABSTRACT

Self-healing coatings are formed by first phosphating or nitriding ferrous parts, then coating with an emulsion of e.g. polysiloxane, oil, sorbitan derivative and sodium sulfonate, butyl cellosolve, oleic acid. Preferred phosphating is to a thickness of 2,000-3,000 mg Zn phosphate/square foot. This coating passes 240-plus hours in 5% salt spray (ASTM B-117) and resists wash off with car wash soap.

This application is a continuation application of U.S. Ser. No. 243,957,filed Sept. 13, 1988, itself a continuation of U.S. Ser. No. 925,584,filed Oct. 30, 1986, which is itself a continuation of U.S. Ser. No.818,437 filed Jan. 13, 1986 all abandoned.

BACKGROUND OF THE INVENTION

(1) Field of the Invention:

The present invention pertains to coatings and metal surface treatmentspreparatory to applying such coatings.

(2) Description of the Prior Art:

Many attempts have been made to improve the salt spray protectionprovided by protective coatings including among others, improvements incompositions of coating materials and also pretreatments prior tocoatings to modify the chemical surface for better bond with theprotective coating.

U.S. Pat. No. 2,528,535 to Merker teaches phosphating oil-in-watersystems for lubricating compositions, preferably with oxidationinhibitors and mentions the possibility of adding and rust corrosioninhibitors, preferably less than 3% by weight.

U.S. Pat. No. 3,457,173 to Pater lubricates metal surfaces by applyingsiloxane-polyoxyalkylene block co-polymers.

Soviet Union Pat. No. 0810782 teaches polymerized cotton seed oilapparently used as a lubricant.

U.S. Pat. No. 4,440,582 to Smith, et al. claims coating compositionsconsisting essentially of phosphating oil, polysiloxane oralkylpolysiloxane and water and expresses a preference for applying suchcoating compositions to metal parts which have been phosphated.

None of the above references teach the surprising improvement obtainedby the present invention's use of sorbitan and preferably also alkalineearth, e.g. barium, sulfonates.

It is particularly surprising that, in spite of the teaching of U.S.Pat. No. 4,440,582 that the compositions should consist essentially of(be restricted to) phosphating oils, silioxanes and water, the presentinvention involves the discovery that very substantial increases inperformance can be obtained by adding one or more of the additionalingredients disclosed herein.

SUMMARY

(1) General Statement of the Invention:

The present invention, by using emulsions produced from oil-basedconcentrates comprising petroleum oils, siloxanes, and organic saltsproduced by reacting polyfunctional long chain organic compounds, e.g.polyamines or polyhydroxides or mixed polyamine/polyhydroxides with anorganic acid provides when measured dramatically improved salt sprayperformance, particularly after car wash or contact with other detergentsolutions. When applied over prepared ferrous metal surfaces, e.g.nitrided, chromated or phosphated ferrous metal work pieces, thecompositions of the invention provide essentially self-healing polymercoatings, particularly suited for use in motor vehicles, militaryequipment, and all sorts of machinery. The invention is applicable tovirtually any phosphated or nitrided work piece requiring substantialcorrosion protection and can provide some protection for even nonferrousworkpieces.

(2) Utility of the Invention:

The invention if useful for protecting metals, particularly ferrous workpieces and especially those which have been previously phosphated ornitrided. While not wishing to be held to any theory of the invention,it appears that the nitriding or phosphating increase the roughness ofthe metal surface, providing irregularities which more firmly grip andbond the coating layer to the metal work piece.

BRIEF DESCRIPTION OF THE DRAWING(S)

FIG. 1 is a graph of salt-spray resistance days for several inventiveand conventional formulations.

FIG. 2 is a schematic diagram of a manufacture according to theinvention.

FIG. 3 is a schematic diagram of a process of the present inventionshowing the phosphatizing followed by the dip coating into the emulsioncompositions of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

(1) Starting Materials:

A. Oil:

The oils useful in the present invention are petroleum-derived, withnaphthenic oils being less preferred and paraffinic being morepreferred. More preferable paraffinic oils include those having an SSUviscosity in the range of about 50 SSU to about 700, more preferably 100to 400 and most preferably 250 to 370 seconds at 38° C. (100° F.).Particularly preferred are oils having a viscosity index of above 90,more preferably above 95.

The oil will preferably comprise from about 20 to 95, more preferably 30to 80 and most preferably 45 to 85 wt % of the total formulation of theinvention concentrate.

B. Glycol Ether:

The invention comprises glycols, glycol ethers and derivatives thereof.Preferred are alkyl carbitols especially Butyl carbitol or mostpreferably, ethylene glycol monobutyl ether e.g. butyl cellosolve orExtasolve manufactured by Eastman Kodak, Rochester.

The glycols, etc. will preferably comprise from about 0.1 to 15, morepreferably 1 to 10 wt. % of the total formulation.

C. Emulsifying Agent:

The invention comprises emulsifying agents such as oxygenatedhydrocarbons partially neutralized with alkaline earth metal (e.g.barium) then blended with alkali metal (e.g. sodium) sulfonatecompositions such as ALOX575 available from ALOX Corp. of Niagara Fallsor IDASOL D274 from Ideas, Inc. Woodale, IL, or similar products from N.L. Kimes, Inc., Allison Park, PA.

The emulsifying agent will preferably comprise about 5 to 50, morepreferably 8 to 35, and most preferably 20 to 30 wt. % of the totalformulation.

D. Siloxane:

Siloxanes useful in the present invention are substituted with one ormore alkyl groups, each alkyl group comprising preferably 1 to stet,more preferably 1 to 6, and most preferably 1 to 5 carbon atoms.

These products are commercially available from Dow Chemical, UnionCarbide, and other suppliers. These are produced from silanes bycondensation reactions to form a silica-oxygen-silica bound are asdescribed in Dow brochure 22-240-A-78.

Preferred alkyl-substituted polysiloxanes are amino-functionalsilicones, such as those described in U.S. Pat. Nos. 3,836,371,3,508,933, 3,890,271 and 3,960,575.

The polysiloxanes will generally comprise from about 0.5 to 10 wt. %,more preferably from 0.5 to 5 wt. % and most preferably from 1 to 4 wt.% of the concentrates of the present invention.

E. Water:

While the concentrate formations may contain 0.01 to 40 wt. % or more ofwater (preferably demineralized), 0.05 to 10 wt. % water is preferredand 0.1 to 5 wt. % is most preferred. Emulsions will generally containabout 50 to 95 wt. % water, or more, with 70 to 90% being morepreferred.

F. Sorbitans:

The polyoxyethylene derivative of fatty acid partial esters of sorbitolanhydrides of the present invention are preferably sorbitan derivativesand, without detracting from the generality, will be so referred tothroughout this application. Without being bound by any theory, itappears that these molecules, having a hydrophobic end which seeks waterand a hydrophobic end which seeks oil, tend to balance and couple theformulation into particularly stable emulsions. It is particularlysurprising that, in addition, these sorbitan derivatives provideincreased corrosion protective performance.

Preferred are the polyfunctional organic compounds e.g. sorbitanmonooleate, sorbitan trioleate, myristates with hydroxy or aminepolyfunctionality.

As mentioned above, the most preferred sorbitan derivative is sorbitanmonooleate (molecular weight equal 465), which is readily availableunder a number of brand names e.g. "Tweens" 20 through 85, "Spans" 20through 85, "Sorbax" (by Chemax of Greenville, SC), etc. from varioussuppliers, Atlas Chemical Division of ICI, Wilmington, DE, e.g. thosedescribed in McCutcheon "Emulsifiers and Detergents", MC Pub. Co., GlenRock, NJ.

While the upper limits are primarily limited by economics, the sorbitanderivatives will generally be used in the formulations of the inventionat levels of about 0.1 to 20 wt. %, more preferably 0.5 to 15 and mostpreferably 1 to 10 weight percent.

G. Organic Acid:

A preferred organic acid derivative is the alkyl carboxylate compositionmarketed by Lubrizol Corporation, Cleveland, under the brand nameLubrizol 5530, an antirust lubricant containing alkyl carboxylatesamines and esters, see U.S. Pat. Nos. 4,237,022 and 4,216,099.

The organic acids which are a preferred but optional ingredient to theinventions of the present invention are preferably 12 to 54 carbonatoms, more preferably 14 to 20 and most preferably 18 (stearic) orisostearic and derivatives thereof, e.g. oleic acid.

Particularly preferred is isotearic acid which is liquid at roomtemperature. The organic acid may possibly somehow react with the aminofunctional polysiloxane ingredient of the compositions, but the functionof the organic acid is not entirely clear. It is known that the additionof organic acid will, in most cases, substantially increase thestability of the concentrate and the performance of the resultingcoatings.

From about 0.1 to 10, more preferably from about 0.5 to 5 and mostpreferably from about 1 to 4 wt. % of the total formulation willpreferably be organic acid.

A preferred organic acid derivative is the alkyl carboxylate compositionmarketed by Lubrizol Corporation, Cleveland, under the brand nameLubrizol 5530, an antirust lubricant containing alkyl carboxylatesamines and esters, see U.S. Pat. Nos. 4,237,022 and 4,216,099.

H. Metal Sulfonate:

A preferred feature of the present invention is the inclusion in theformulations of organic alkyl carboxylates sulfonates. For bestcorrosion protection, it has been discovered that the preferred organicsulfonates are overbased. (i.e., made with an excess of calcium, bariumor other metal carbonate).

The preferred sulfonates are overbased with barium, calcium, potassiumor sodium, and have sufficient equivalent weight to provide extendedrust protection against corrosive environments. The preferableequivalent weights of these carboxylate, which are derived from alkyls,are as follows when overbased with the following metal sulfonates:sodium sulfonate with equivalent weight preferably 370 to 750, morepreferably 400 to 650 and most preferably 450 to 600, barium sulfonateof a equivalent weight preferably 400 to 1400, more preferably 700 to1300, most preferably 800 to 1200; and calcium sulfonate of a equivalentweight preferably 370 to 850, more preferably 400 to 800, mostpreferably 500 to 750.

The organic sulfonates of the present invention will generally beemployed in quantities of from about 1 to 60%, more preferably fromabout 5 to 40% and most preferably from about 5 to about 30% based onthe total weight of the formulation.

The preferred chain length is from about 10 to 30, more preferably 12 to24 and most preferably 16 to 20 carbon atoms. Molecular weights arepreferably 10 to 50, more preferably 15 to 40 and most preferably 20 to30.

I. Amine:

About 0.1 to 10 wt. % alkanol amine, preferably triethanol amine, may beadded to provide additional wetability and stability where needed.

J. Miscellaneous Optional Additives:

Optional conventional ingredients might also be added, e.g. pigments,dyes, etc.

(2) Surface Treatment Processes:

Surface treatment processes can be conventional such as chromate, andparticularly preferred are nitriding or phosphating.

See generally Kirk and Othmer, "Encyclopedia of Chemical Technology, 2nded., vol. 18 (1969), pp 282-303 and the later editions.

Phosphating can be accomplished by the conventional techniques such asthose set forth in "Practical Phosphate Coatings", Mangill Company, andU.S. Pat. Nos. 3,967,947, 2,465,247, 3,686,031, 4,419,199, 4,539,051 and4,540,637 and references thereto. For automotive uses, preferredphosphating is to a thickness of at least 200-3000 mg zincphosphate/square foot of workpiece.

Nitriding can be either salt bath or fluidized bed nitriding such as thecommercial processes "Tuff Tride", "Melonite", "QPQ"(Quench-Polish-Quench, in which salt bath nitriding is followed byquench in an oxidizing salt bath, followed by mechanical polishing, anda second quench), or fluidized bed nitriding as described in "FluidizedBed Furnace Heat Treating Applications for the Dye Casting Industry",JAPKA, May-June, 1983, Dye Casting Engineer. Miscellaneous surfacetreatment processes which may be employed with the invention includeProcedyne's "Dyna-Case Surface Hardening Treatment", deep casecarburizaton in a fluidized furnace by adding methanol which isvaporized and mixed with nitrogen and a small amount of natural gas toform a synthetic endothermic atmosphere within the treating furnace atabout 899°-1010° C. (1650°-1850° F.) for 1-8 hours, carbonitriding at815°-871° C. (1500°-1600° F.) for 10 minutes--1 hour, followed byquenching; nitriding by adding nitrogen from raw ammonia onto thesurface of the material at 510°-593° C. (950°-1100° F.) to provide acase of 0.0001-0.015 inches deep; nitrocarburizing providing a case of0.0005-0.0020 inches deep by contacting mixtures of natural gas and rawammonia in a fluid be furnace at 566°-621° C. (1050°-1150° F.) for 0.5-2hours; steam bluing in a fluid bed furnace at 343°-538° C. (650°-1000°F.) for 20 minutes--1 hour to provide a blue or black surface, or evencombinations of these conventional surface treatment processes.

(3) Concentrate Preparation:

Apparatus: The apparatus for the present invention will be thatconventionally utilized in the preparation of coatings compositions,e.g. kettles and mixing tanks having flow metering or measuring devicesand agitation means, e.g. pumps mounted on side-arms connecting with themain vessel, internal stirrers, contra-rotating shearing devices and anyof the other available devices which are well known to the art.

Temperature: The temperature during mixing may be different duringdifferent stages in the formulation. These temperatures are not narrowlycritical and will vary to provide faster mixing or better compatibilityof ingredients according to observation of those skilled in the art. Forexample, pressure vessels may be utilized for the purpose of loweringingredient melting and boiling points, where useful, in order to providebetter dispersion of difficult-to-mix ingredients.

Mixing Procedure: While the formulations of the present invention may bemanufactured continuously if desired, batch techniques will be moreusually employed. The sorbitan derivatives are then mixed in and thefinished formulation is allowed to cook with, preferably, constantagitation, after which the formulation is drawn off into shippingcontainers, e.g. tank cars, tank trucks, drums or smaller cans.

Quality Control: The finished formulation, prior to packaging, willgenerally be checked for viscosity, freeze-thaw stability,corrosion-protection under accelerated conditions and other testutilizing techniques well known to the coatings industry.

Application: The formulations of the present invention may be applied tosubstrates to be protected by conventional application techniques, suchas spraying, brushing, dipping, flow-coating, dipspinning, "Filwhirl",or airless spraying. Coating thickness can be varied by changing theformulation, the number of coats, or the amount applied per coat but ingeneral will be in the range from about 2 to about 5 mils after drying.

(4) Emulsion Preparation

The concentrate (e.g. prepared according to Example 1) is diluted with 1to 20, or more preferably 2 to 15, and most preferably 3 to 8 parts byweight of water to form the emulsion which is applied to the workpieces.Dilution is preferably about 38° C. (100° F.), more preferably above 52°C. (125° F.), and most preferably at 52°-71° C. (125°-160° F.).

(5) Batch or Continuous Basis:

While the examples describe the invention on a batch basis, it may come,of course, to be practiced on a continuous basis with continuous flowsof starting materials into the mixing vessel and with continuous coatingtechniques e.g. roller coating continuous conveyor or even continuouswork piece e.g. sheet steel moving continuously through a dip tank.

(8) Examples:

EXAMPLE I (Formulation According to the Invention Providing ExcellentSalt Spray Resistance and Shelf Life)

A conventional steam jacketed mixing kettle equipped with rotary stirrerare added 66 parts by weight of naphthanic oil having a viscosity of 100SSU at 38° C. (100° F.) and purchased as McMillan and 100 VR which isheated to 54° C. (130° F.). To the oil is added 20 parts by weight ofemulsifying agent, ALOX 575 purchased from ALOX Corp., Niagara Falls 5parts by weight in the form of butyl cellosolve from Eastman KodakCompany, Rochester, NY, 2 parts by weight sorbitan derivative assorbitan monooleate purchased from Chemax Corp. of Greenville, SC, asSorbax SMO and 1 part by weight sodium sulfonate as an additionalemulsifier. Stirring continues during addition as a premixed compositionpurchased commercially, are added together 2.46 parts by weightpolysiloxane as Dow 536, 2.46 parts by weight alkanolamide emulsifier asWitcamide 511 and 1.08 parts by weight of isostearic acid, althoughthese could be added alternatively by reacting the isostearic acid withthe polysiloxane. Heating is stopped but stirring is continued about 20minutes to ensure a homogenious mixture. The contents of the mixingvessel are then sampled, quality control tests for viscosity, stabilityand appearance are run and the formulation is draw off into 55 gallondrums. (Water is not added separately because the individual ingredientscontain about 0.5 parts by weight based on the weight of the totalformulation of water.)

The resulting formulation is tested for corrosion protection by applyingit to a ferrous work piece which has been previously phosphated byconventional techniques, by dipping the work piece into an emulsionformed by adding one part by volume of the above formulation with 4parts by volume of demineralize water. After drying for 24 hours, thetest work piece is subjected to a 5% neutral pH salt (NaCl) spray at attemperature of 35° C. (95° F.) according to ASTB-117. The test panelresists failure (corrosion) for 39 days (936 hours).

A sample of the above formulation (undiluted) survives 5 successivefreeze-fall cycles each comprising 16 hours at -18° C. (0° F.) followedby 8 hours at 25° C. (77° F.) with no separation or other evidentdeleterious effects.

A sample of emulsion (diluted as specified above) shows no significantseparation (i.e., less than 2% "cream") upon standing at roomtemperature for 24 hours.

When a work piece as previously described is dipped into the aboveformulation (diluted) and allowed to dry at room temperature atapproximately 50% relative humidity, the coating is cured and cured in24 hours. But remains self-healing i.e., scratch made with a scribeheals to protect the metal for about 24 hours.

(For comparison, a similar but unoiled phosphated workpiece fails inless than 48 hours and a similar but unoiled nitrided workpiece fails inless than 72 hours of salt spray.)

EXAMPLE II (Comparative According to U.S. Pat. No. 4,440,582)

When a formulation is prepared according to the techniques described inU.S. Pat. No. 4,440,582 by repeating the techniques of Example II below,but omitting the sorbitan monooleate (Chemax Sorbax SMO) and theemulsifying agent (ALOX 575) and retaining the oil, the amino functionalsilioxane (Dow 536), the oil and the alkanolamide and isostearic acidand other ingredients in the parts by weight as specified in Table I, astested similarly to the tests described in Example I, the work pieceexposed to the same salt spray fails after 26 days (624 hours), areduction in salt spray failure time of about 33% as compared to theformulation of the present invention.

EXAMPLE III (Comparative-Without Silioxane)

When a formulation is prepared according to the techniques of Example I,but using as ingredients only oil, emulsifier (sodium sulfonate),organic acid (oleic acid), and triethanol amine, both an extra corrosioninhibitor (high molecular weight from Ideas, Inc.) and a conventionaldefoamer from Diamond Shamrock, Morristown, NJ, the salt spray timefailure is only 9 days (216 hours).

EXAMPLE IV (According to the Invention but Omitting the SorbitanMonooleate Stabilizer)

When a formulation is prepared according to the techniques of Example 1and using the same parts by weight except that the sorbitan monooleatestabilizer is omitted the work piece treated with the dilutedformulation in accordance with the techniques of Example 1 survives 38days (816 hours) in the salt spray before failure, a substantialimprovement over the comparative formulation of Example 2, but slightlyless than the preferred formulation of Example 1. However, theformulation exhibits substantial separation during a 24 hour roomtemperature test on the undiluted concentrate.

EXAMPLE V (Invention, Substituting Paraffinic Oil)

When the techniques and tests of Example 1 are repeated but substitutinga paraffinic oil for the naphthanic oil employed in Example 1, theresulting formulation survives 44 days (1056 hours) of salt spray testand the formulation is stable in both concentrated and emulsion form.This preferred formulation shows the superiority of the results obtainedwhen paraffinic oil is substituted for naphthanic oil.

EXAMPLE VI (Invention With Stabilizer, Paraffinic Oil and MetalSulfonate)

When a formulation is prepared according to the techniques of Example V,but additionally adding 10 parts by weight of a metal sulfonate asLubrizol 5530, leaving further improved salt spray resistance of 54 days(1296 hours) to failure are observed. The formulation is stable in boththe concentrated and emulsion forms. This Example illustrates the mostpreferred formulation of the invention with salt spray resistance ofmore than twice that of the prior art compared to the Example II.

EXAMPLE VII (Invention Used on Nitrided Workpiece)

When Example VI is repeated, substituting a nitrided workpiece for thephosphated workpiece, 42 days excellent protection is obtained, but thetest is terminated before failure.

                                      TABLE 1                                     __________________________________________________________________________               I   II  III IV  V   VI  VII*                                       EXAMPLE    Inv.                                                                              Comp.                                                                             Comp.                                                                             Inv.                                                                              Inv.                                                                              Inv.                                                                              Inv.                                       __________________________________________________________________________    A.                                                                              Oil                                                                           100 Pale 66  76.1                                                                              83.5                                                                              --  --  --  --                                           330 Neutral                                                                            --  --  --  --  53.35                                                                             43.35                                                                             53.35                                      B.                                                                              Glycol   5.0 1.0 --  5.0 4.8 4.8 4.8                                          Butyl Cellosolve                                                            C.                                                                              Emulsifying                                                                            20  --  --  28.5                                                                              27.4                                                                              27.4                                                                              27.4                                         Agent                                                                         ALOX 575                                                                    D.                                                                              Siloxane 2.46                                                                              2.46                                                                              --  2.46                                                                              2.85                                                                              2.85                                                                              2.85                                         (aminofunctional                                                              silicone,                                                                     Dow 536)                                                                    E.                                                                              Water    --  --  --  --  --  --  --                                           (demineralized)                                                             F.                                                                              "Sorbitan"                                                                             2   --  --  --  5.4 5.4 5.4                                          Sorbitan                                                                      Monooleate                                                                  G.                                                                              Organic Acid                                                                           --  1.0 1.0 --  1.0 1.0 1.0                                          Oleic Acid                                                                  H.                                                                              alkylcarboxylate                                                                       --  --  --  --  --  10  --                                           Lubrizol 5530                                                               I.                                                                              Misc. Ing.                                                                    Sodium sulfonate                                                                       1   12  12  --  1.1 1.1 1.1                                          Witcomide 511                                                                          2.46                                                                              2.46                                                                              --  2.46                                                                              2.85                                                                              2.85                                                                              2.85                                         Isostearic Acid                                                                        1.08                                                                              1.08                                                                              --  1.08                                                                              1.25                                                                              1.25                                                                              1.25                                         Triethanolamine                                                                        --  1.5 1.0 --  --  --  --                                           High MW  --  2.0 2.0 --  --  --  --                                           Sulfonate                                                                     Nopco NDW                                                                              --  .5  .5  --  --  --  --                                         J.                                                                              Tests                                                                         Salt Spray (days)                                                                      39  24  9   38  44  42+                                              Stability (24 hrs)                                                            Concentrate                                                                            pass                                                                              pass                                                                              pass                                                                              fail                                                                              pass                                                                              pass                                                                              pass                                         Emulsion (20%)                                                                         pass                                                                              pass                                                                              pass                                                                              pass                                                                              pass                                                                              pass                                                                              pass                                         Self Healing?                                                                          yes yes no  yes yes yes yes                                                           oily                                                       __________________________________________________________________________     *Nitrided workpiece; + = Test terminated before failure                  

MODIFICATIONS

Specific compositions, methods, or embodiments discussed are intended tobe only illustrative of the invention disclosed by this Specification.Variation on these compositions, methods, or embodiments are readilyapparent to a person of skill in the art based upon the teachings ofthis specification and are therefore intended to be included as part ofthe inventions disclosed herein. For example, the formulation maycontain biocides, antifoamers, dyes, pigments, etc.

Reference to patents made in the specification is intended to result insuch patents being expressly incorporated herein by reference includingany patents or other literature references cited within such patents.

What is claimed is:
 1. A manufacture comprising a metal substrate havinga surface treated by chromate, phosphate or nitride processes coatedwith a coating composition comprising in combination:A. at least 20percent by weight aliphatic or naphthenic oil having a viscosity ofabout 50 to 500 second (SSU @ 37° C., 100° F.); B. stabilizing agentcomprising glycol or glycol ethers or derivatives thereof; C. about 5 to50 percent by weight emulsifying agent comprising a sulfonate salt ofalkaline earth metals; D. siloxane resin comprising polyalkylsiloxane oralkylpolysiloxane or derivatives thereof; E. water.
 2. A manufactureaccording to claim 1 wherein the metal substrate comprises ferrousmetal.
 3. A manufacture according to claim 2 wherein said compositionadditionally comprises about 0.1 to 20 wt. % of a mono or polyoleateorganic salt of a long chain poly functional organic polyamine orpolyhydroxide compound.
 4. A manufacture according to claim 2 whereinsaid composition additionally comprises a sulfonate of barium or calciumor mixtures thereof.
 5. A manufacture according to claim 2 wherein thesulfonate salt is overbased by an excess of barium or calcium.
 6. Amanufacture according to claim 1 wherein the oil is substantiallyparaffinic oil having a viscosity of about 250-370 seconds SSU at 37°C., 100° F.
 7. A manufacture according to claim 2 wherein thecomposition comprises:(a) about 60 to 97 wt. % of component A; (b) about0.1 to 15 wt. % of component B; (c) about 5 to 50 wt. % of component C;(d) about 0.5 to 10 wt. % of component D; (e) about 0.1 or more % ofcomponent E.
 8. A manufacture comprising a metal substrate which has anitrided, carbonized, carbo nitrided, nitro carbonized, steam blued orphosphated surface coated with a coating composition comprising incombination:A. at least 20 percent by weight aliphatic or naphthenic oilhaving a viscosity of about 50 to 500 second (SSU @ 37° C., 100° F.); B.stabilizing agent comprising glycol or glycol ethers or derivativesthereof; C. about 5 to 50 percent by weight emulsifying agent comprisinga sulfonate salt of alkaline earth metals; D. siloxane resin comprisingpolyalkylsiloxane or alkylpolysiloxane or derivatives thereof; E. water.